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at:tutorial:distribution [2009/01/29 15:38] elisagat:tutorial:distribution [2009/01/29 15:42] elisag
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 A leased object reference is a remote far reference that grants access to a remote object for a limited period of time. When the time period has elapsed, the access to the remote object is terminated and the leased reference is said to //expire//. Similarly to remote far references, a leased reference abstracts client objects from the actual network connection state. Client objects can send a message to the remote object even if a leased references is disconnected at that time. Message are accumulated in order to be transmitted when the reference becomes reconnected. When the leased reference expires it, messages are discarded since an expired leased reference behaves as a //permanently// disconnected remote far reference. The figure below shows a diagram of the different states of a leased reference. A leased object reference is a remote far reference that grants access to a remote object for a limited period of time. When the time period has elapsed, the access to the remote object is terminated and the leased reference is said to //expire//. Similarly to remote far references, a leased reference abstracts client objects from the actual network connection state. Client objects can send a message to the remote object even if a leased references is disconnected at that time. Message are accumulated in order to be transmitted when the reference becomes reconnected. When the leased reference expires it, messages are discarded since an expired leased reference behaves as a //permanently// disconnected remote far reference. The figure below shows a diagram of the different states of a leased reference.
  
-{{ :at:tutorial:leasedref-state.png |:at:tutorial:leasedref-state.png}}+{{ :at:tutorial:leasedref-state.png |:at:tutorial:leasedref-state.png?160x30}}
  
 ====Working with leased object references==== ====Working with leased object references====
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 </note> </note>
  
-More information pertaining to the API of the leased references language module can be found in the appendix.+More information pertaining to the API of the leased references language module can be found in the [[appendix|appendix]].
  
 ===== Taking Offline Remote Objects ===== ===== Taking Offline Remote Objects =====
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 <note> <note>
-Leased object references make use of the ''takeOffline:'' primitive to terminate the access to a remote object once the lease time elapses. Note that the ''takeOffline'' primitive can be considered the equivalent to the so-called [[http://en.wikipedia.org/wiki/Manual_memory_management|''delete'' operation]] provided by some sequential languages without built-in local garbage collection.  Rather than using this primitive for garbage collection purposes, regular AmbientTalk developers are encouraged to make use of the high-level language constructs for leasing explained in the previous section which aids them to deal with both transient and permanent disconnections and properly reclaim their remote objects.+[[distribution#dealing_with_permanent_failures|Leased object references]] make use of the ''takeOffline:'' primitive to terminate the access to a remote object once the lease time elapses. Note that the ''takeOffline'' primitive can be considered the equivalent to the so-called [[http://en.wikipedia.org/wiki/Manual_memory_management|''delete'' operation]] provided by some sequential languages without built-in local garbage collection.  Rather than using this primitive for garbage collection purposes, regular AmbientTalk developers are encouraged to make use of the high-level language constructs for leasing explained in the previous section which aids them to deal with both transient and permanent disconnections and properly reclaim their remote objects.
 </note> </note>
  
at/tutorial/distribution.txt · Last modified: 2009/01/30 16:13 by tvcutsem